OBJECTIVE: To eliminate graft versus host reactivity (GVH) from allogeneic murine bone marrow and utilize this marrow in combination with chemotherapy and/or irradiation to treat several models of murine leukemia and lymphoma. APPROACH: Recruit (or trap) recirculating lymphocytes with specific GVH reactivity in the marrow donor's lymphoid organs (other than marrow) thereby deleting these cells from his marrow. Lymphocytes with specific GVH reactivity will be recruited to the appropriate lymphoid organ by challenging this organ with allogeneic cells. Initially we will define the optional conditions to recruit the maximum number of specifically reactive lymphocytes, and then use these conditions to delete the donor's marrow of specific GVH reactivity as defined by the popliteal lymph node GVH and GVH mortality assays. This marrow will then be used to reconstitute and possibly mount a graft versus leukemia reaction in leukemic allogeneic recipients previously treated with chemotherapy and/or irradiation.